【 Devices and keys. Secret passages. 】

[anselnettles]

"• The 2 previous points obviously mean that your game must contain animations,
various devices like door opening systems, keys and ways to use them, elevators
and secret passages."

[anselnettles]

The "secret passages" are now marked R in the map file. In front of them we would need a sprite or a block that can be removed via an item or a projectile, or similar.